Vauxhall M32 6-speed manual transmission.

Background Information

Bearing failure on the M32 gearbox is common more so on vehicles which have been tuned, however standard vehicles also suffer.

Typically you will notice a whining noise when cruising on the motorway in 6th gear. The whining will come and go as you press and release the accelerator. When the bearings wear even more, the gearstick will begin to move as you press/release the clutch in first gear. Minor movements may be due to other things so don’t panic at any movement. The movement is a few cm and very noticeable.

Eventually you may start to see movement in 5th and 6th gear as well, if you see this occurring your gear box really is on borrowed time.


Vehicles Affected

Vauxhall have used the M32 gearbox across a wide range of cars, the table below gives an indication of where they were used. It should be noted that to combat the failures, the latest M32 gearbox has been modified in an attempt to get greater oil flow around the enlarged 6th gear bearing.

Astra HAstra JCorsa DInsigniaMerivaMokkaVectra C / SignumZafira B

Failure Mode

Bearing fatigue and failure is the most common cause of catastrophic failure of the M32 gear box.

The most common bearing to fail first is the one which sits above 6th gear. The photos which follow were from my own failed gearbox which show this 6th gear bearing failure.

 Failed bearing is at the top of the photo

Failed bearing is at the top of the photo

 Excessive play and loose rollers

Excessive play and loose rollers

 Bearing becomes pitted due to metal fatigue

Bearing becomes pitted due to metal fatigue

Providing action is taken before any of the bearings entirely fail the gearbox can be repaired by replacing the bearings throughout. This works out much cheaper than replacing the whole unit. It is possible to split the casing and remove the gears without removing the box from the car, saving the amount of work necessary.

Gearbox Technical Information

The M32-6 is a 6-speed manual transmission. This transmission is being used for the first time in the Astra-H in conjunction with the Z 20 LEL DOHC II turbocharged petrol engine. This manual transmission is an all-synchromesh 3-shaft transmission.
This 3-shaft transmission has the following advantages:

  • Compact construction
  • Improved smooth-running performance
  • Better shift quality
  • High torque transmission
  • Low weight

Structure of the manual transmission

Location of the shafts
The following cross-sectional diagram shows the location of the respective shafts in the M32-6 transmission, as per the 3-shaft principle.
1Upper main shaft3Lower main shaft
2Input shaft4Differential gear

In this transmission angular cone bearings are used for all shafts. These bearings require a certain amount of play and pretension. The required amount of bearing play and pretension is achieved at the production stage by using shims under the angular cone bearing in the transmission housing.

Location of gearwheels

This diagram shows the location of the gearwheels on the respective shaft.

Lower main shaftInput shaft with 1st/2nd gearUpper main shaft
11st gear gearwheel53rd/5th gear gearwheel84th gear gearwheel
22nd gear gearwheel66th gear gearwheel9Reverse gear gearwheel
35th gear gearwheel74th gear gearwheel103rd gear gearwheel
46th gear gearwheel

One particular advantage of this 3-shaft transmission is that on the input shaft, the 3rd gear gearwheel is also used for 5th gear.

Power flow in the individual gears

The following diagrams show the flow of power in the individual gears.


 1st Gear

1st Gear

 2nd Gear

2nd Gear

 3rd Gear

3rd Gear

 4th Gear

4th Gear

 5th Gear

5th Gear

 6th Gear

6th Gear

 Reverse Gear

Reverse Gear

Location of components in the M32-6 transmission

The following exploded diagram shows the location of the components in the M32-6 manual transmission. The components of the individual shafts will then be described.

1Axle shaft seal ring6Axle shaft seal ring
2Guide sleeve - differential housing7Shim
3Differential housing8Differential assembly
4Seal ring - axle shaft seal ring sealing flange9Transmission housing
5Axle shaft seal ring sealing flange
10Upper main shaft assembly16Central release
11Input shaft assembly17Pressure line
12Lower main shaft assembly18Clutch housing
13Clutch bleed connector19Gearshift assembly
14Fastening sleeve20Magnet
15Reversing light switch21Oil baffle plate

Location of components in upper main shaft assembly

1Fluid collector pipe16Synchro ring
2Upper main shaft173rd/4th gear shift sleeve
3Roller bearing - upper main shaft18Thrust piece
4Retaining ring19Synchroniser body
5Needle roller bearing - reverse gear20Retaining ring
6Reverse gear gearwheel (driven)21Shim
7Reverse gear shift sleeve22Roller bearing - main shaft
8Synchro ring - reverse gear23Needle roller bearing - 4th gear gearwheel
9Thrust piece244th gear gearwheel
10Synchroniser body25Intermediate ring
11Spacer26Synchro ring
12Retaining ring273rd/4th gear shift fork
133rd gear gearwheel (driven)28Gear shift shaft
14Needle roller bearing - 3rd gear gearwheel29Reverse gear shift fork
15Intermediate ring

Location of components – lower main shaft assembly

1Thrust piece196th gear gearwheel (driven)
2Retaining ring20Needle roller bearing - 6th gear
31st/2nd gear shift sleeve21Roller bearing - main shaft
4Outer synchro ring22Shim
5Intermediate ring235th/6th gear shift fork
6Inner synchro ring24Gear shift shaft
72nd gear gearwheel (driven)251st/2nd gear shift fork
8Needle roller bearing - 2nd gear gearwheel26Synchroniser body
9Locking ring27Outer synchro ring
10Pressure piece28Intermediate ring
115th gear gearwheel (driven)29Inner synchro ring
12Needle roller bearing - 2nd gear gearwheel301st gear gearwheel (driven)
13Synchro ring31Needle roller bearing - 1st gear gearwheel
14Thrust piece32Retaining ring
15Synchroniser body33Roller bearing - main shaft
16Retaining ring34Main shaft
175th/6th gear shift sleeve35Fluid collector pipe
18Synchro ring

Location of components – input shaft assembly

1Input shaft seal ring7Shim
2Roller bearing8Input shaft bearing
3Input shaft96th gear gearwheel (driving)
41st gear gearwheel (driving)104th gear gearwheel (driving)
52nd gear gearwheel (driving)11Spacer
6Input shaft bolt123rd/5th gear gearwheel (driving)


An improved synchronisation system, already fitted to the F40 manual transmission, is used on the M32-6 transmission. The previous sliding blocks and synchro springs have been dispensed with and have been replaced with thrust pieces.

Matched synchronisation systems are also used for the individual gears.

Two and three-cone synchronisation systems are used.

The synchronisation systems used for each respective gear will be shown in the following.

1st/2nd gearThe three-cone synchronisation system is used for these two gears.
1.Inner synchro ring
2.Intermediate ring
3.Outer synchro ring
4.Shift sleeve
5.Synchroniser body
6.Thrust pieces

3rd/4th gear

A two-cone synchronisation system is used for these two gears.

1.Intermediate ring
2.Synchro ring
3.Shift sleeve
4.Synchroniser body

5th/6th gear

A single-cone synchronisation system is used for these two gears.

1. Synchro ring
2. Shift sleeve
3. Synchroniser body

Reverse gear

Like 5th/6th gear, reverse gear also features a single-cone synchronisation system.


The M32-6 manual transmission also has a cable gearshift. The individual gears are selected by means of a central gearshift unit.

Mark for the M32-6 manual transmission

The mark for the M32-6 manual transmission consists of a bar code and a combination of numbers.

The letters and numbers located below the bar code have the following meanings:

1M32Transmission type
2O"Opel" design
3FAM2Engine family
5CWheel set
6XXXXXXXXSerial number
7NRTransmission code

Transmission fluid

The M32-6 manual transmission uses the same transmission fluid as the F13 / F17 / F17+ / F23 / F25 / F35 and F40 transmissions.

The transmission’s fluid fill quantity is 2.4 litres.

Container sizeCatalogue numberPart number
1 litre SAE 8019 40 7689 120 541
60 litres SAE 8019 40 7109 194 349

Technical data

The maximum input torque for the M32-6 manual transmission is <strong>320 Nm.</strong>

The weight of the M32-6 manual transmission is approx. 41.5 kg without fluid.

The overall length of the transmission is 329.5 mm.

Transmission ratio

EngineZ 20 LEL
1st gear3.818
2nd gear2.053
3rd gear1.302
4th gear0.935
5th gear0.744
6th gear0.614
Reverse gear3.727
Output ratio3.94